To advance the work already performed in our laboratory with rats, adrenal medulla was grafted to the denervated putamen of the rhesus monkey in our continuing research on brain tissue transplantation. Graft survival is erratic. In the most successful animal, the behavioral response produced by the graft has lasted one year. An instrument (the brain grafter) that facilitates grafting was developed and a patent applied for. Adrenal survival may be enhanced by the addition of nerve growth factor and other trophic factors.